ASTM C856-17
(Practice)Standard Practice for Petrographic Examination of Hardened Concrete
Standard Practice for Petrographic Examination of Hardened Concrete
ABSTRACT
This practice outlines the standard procedures for performing petrographic examination of hardened concrete samples. The samples examined may be taken from concrete constructions, that is, all sorts of objects, units, or structures that have been built of hydraulic cement concrete. They may also be concrete products or portions thereof, or concrete or mortar specimens that have been exposed in natural environments or simulated service conditions, or subjected to laboratory tests. This practice applies to samples of all types of hardened hydraulic-cement mixtures, including concrete, mortar, grout, plaster, stucco, terrazzo, and the like. The equipments generally used for specimen preparation are diamond saw, cutting lubricant, horizontal lap wheels, free abrasive machine, polishing wheel, hot plate or oven, prospector's pick and/or bricklayer's hammer, abrasives, plate-glass squares, suitable media, and microscope slides. For specimen examination, the equipments needed are stereomicroscope, dollies, petrographic or polarizing microscope, metallographic microscope, eyepiece micrometer, stage micrometer, microscope lamps, needleholders and points, bottles with droppers, assorted forceps, lens paper, refractometer, and immersion media. Appropriate procedures for the sampling, preparation, and examination of specimens are detailed methodically.
SCOPE
1.1 This practice outlines procedures for the petrographic examination of samples of hardened concrete. The samples examined may be taken from concrete constructions, they may be concrete products or portions thereof, or they may be concrete or mortar specimens that have been exposed in natural environments, or to simulated service conditions, or subjected to laboratory tests. The phrase “concrete constructions” is intended to include all sorts of objects, units, or structures that have been built of hydraulic cement concrete.
Note 1: A photographic chart of materials, phenomena, and reaction products discussed in Sections 8 – 13 and Tables 1-6 are available as Adjunct C856 (ADJCO856). (A) A substantial portion of the coarse aggregate has maximum dimensions in the range shown as measured on sawed or broken surfaces.(B) Sections sawed or drilled close to and parallel to formed surfaces appear to show local turbulence as a result of spading or rodding close to the form. Sections sawed in the plane of bedding (normal to the direction of placement) are likely to have inconspicuous orientation. Sections broken normal to placement in conventionally placed concrete with normal bond tend to have aggregate knobs abundant on the bottom of the upper piece as cast and sockets abundant on the top of the lower piece as cast. (A) Dana, E. S., Textbook of Mineralogy, revised by W. E. Ford, John Wiley & Sons, New York, N. Y., 4th ed., 1932, pp. 273–274.(B) Pore visible to the naked eye, or at × _, or sucks in water that is dropped on it.(C) Dark solid spheres or hollow-centered spheres of glass, or of magnetite, or some of glass and some of magnetite, recognizable at magnification of × 9 on sawed or broken surfaces. Other mineral admixtures with characteristic particles visible at low magnification are recognizable. Ground surface of concrete containing portland blast-furnace slag cement are unusually white near-free surfaces but retain greenish or blue-greenish patches, and slag particles can be seen with the stereomicroscope or polarizing microscope. (A) Secondary ettringite can sometimes be recognized by crystal habit and silky luster.(B) Fly ash can be detected by color and shape when dark spheres are present. In concrete that has not oxidized the presence of slag may be inferred from the green or blue color of the paste.(C) Ettringite and calcium hydroxide in voids may be recognized by their crystal habits.(D) Magnesium oxide and calcium oxide should be identifiable in polished section. (A) The literature and private reports include data on many unidentified second...
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Designation: C856 − 17
Standard Practice for
1
Petrographic Examination of Hardened Concrete
This standard is issued under the fixed designation C856; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope* 1.5 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This practice outlines procedures for the petrographic
responsibility of the user of this standard to establish appro-
examination of samples of hardened concrete. The samples
priate safety and health practices and determine the applica-
examined may be taken from concrete constructions, they may
bility of regulatory limitations prior to use. A specific hazard
be concrete products or portions thereof, or they may be
statement is given in 6.2.10.1.
concreteormortarspecimensthathavebeenexposedinnatural
environments, or to simulated service conditions, or subjected
2. Referenced Documents
to laboratory tests. The phrase “concrete constructions” is
2
2.1 ASTM Standards:
intended to include all sorts of objects, units, or structures that
C125Terminology Relating to Concrete and Concrete Ag-
have been built of hydraulic cement concrete.
gregates
NOTE 1—A photographic chart of materials, phenomena, and reaction
C215 Test Method for Fundamental Transverse,
products discussed in Sections8–13 and Tables 1-6 are available as
Longitudinal, and Torsional Resonant Frequencies of
Adjunct C856 (ADJCO856).
Concrete Specimens
1.2 The petrographic procedures outlined herein are appli-
C227 Test Method for Potential Alkali Reactivity of
cable to the examination of samples of all types of hardened
Cement-Aggregate Combinations (Mortar-Bar Method)
hydraulic-cement mixtures, including concrete, mortar, grout,
C342Test Method for PotentialVolume Change of Cement-
3
plaster, stucco, terrazzo, and the like. In this practice, the
Aggregate Combinations (Withdrawn 2001)
material for examination is designated as “concrete,” even
C441TestMethodforEffectivenessofPozzolansorGround
though the commentary may be applicable to the other
Blast-Furnace Slag in Preventing Excessive Expansion of
mixtures, unless the reference is specifically to media other
Concrete Due to the Alkali-Silica Reaction
than concrete.
C452Test Method for Potential Expansion of Portland-
1.3 Thepurposesofandproceduresforpetrographicexami- Cement Mortars Exposed to Sulfate
nationofhardenedconcretearegiveninthefollowingsections: C457Test Method for Microscopical Determination of Pa-
rameters of the Air-Void System in Hardened Concrete
Section
C496/C496MTest Method for Splitting Tensile Strength of
Qualifications of Petrographers and Use of Technicians 4
Cylindrical Concrete Specimens
Purposes of Examination 5
C597Test Method for Pulse Velocity Through Concrete
Apparatus 6
Selection and Use of Apparatus 7
C803/C803MTest Method for Penetration Resistance of
Samples 8
Hardened Concrete
Examination of Samples 9
C805Test Method for Rebound Number of Hardened Con-
Specimen Preparation 10
Visual and Stereomicroscope Examination 11
crete
Polarizing Microscope Examination 12
C823Practice for Examination and Sampling of Hardened
Paste Features 13
Concrete in Constructions
Report 14
C1012Test Method for Length Change of Hydraulic-
1.4 Thevaluesstatedininch-poundunitsaretoberegarded
Cement Mortars Exposed to a Sulfate Solution
as the standard. The SI units in parentheses are provided for
C1260Test Method for Potential Alkali Reactivity of Ag-
information purposes only.
gregates (Mortar-Bar Method)
1 2
This practice is under the jurisdiction of ASTM Committee C09 on Concrete For referenced ASTM standards, visit the ASTM website, www.astm.org, or
andConcreteAggregatesandisthedirectresponsibilityofSubcommitteeC09.65on contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Petrography. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Jan. 1, 2017. Published March 2017. Originally the ASTM website.
3
approved in 1977. Last previous edition approved in 2014 as C856 – 14. DOI: The last approved version of this historical standard is referenced on
10.1520/C0856-17. www.astm.org.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
C856 − 17
5
TABLE 1 Visual Examination of Concrete (1)
Coarse Aggregate + Fine Aggregate + Matrix + Air + Embedded Items
Composition:
A
Maximum dimension, in. or
mm, in the rang
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: C856 − 14 C856 − 17
Standard Practice for
1
Petrographic Examination of Hardened Concrete
This standard is issued under the fixed designation C856; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This practice outlines procedures for the petrographic examination of samples of hardened concrete. The samples examined
may be taken from concrete constructions, they may be concrete products or portions thereof, or they may be concrete or mortar
specimens that have been exposed in natural environments, or to simulated service conditions, or subjected to laboratory tests. The
phrase “concrete constructions” is intended to include all sorts of objects, units, or structures that have been built of hydraulic
cement concrete.
NOTE 1—A photographic chart of materials, phenomena, and reaction products discussed in Sections 8 – 13 and Tables 1-6 are available as Adjunct
C856 (ADJCO856).
1.2 The petrographic procedures outlined herein are applicable to the examination of samples of all types of hardened
hydraulic-cement mixtures, including concrete, mortar, grout, plaster, stucco, terrazzo, and the like. In this practice, the material
for examination is designated as “concrete,” even though the commentary may be applicable to the other mixtures, unless the
reference is specifically to media other than concrete.
NOTE 2—Appendix X1 outlines an uranyl acetate method for identifying locations where alkali-silica gel may be present. It is a requirement that the
substances in those locations must be identified using any other more definitive techniques, such as petrographic microscopy.
1.3 The purposes of and procedures for petrographic examination of hardened concrete are given in the following sections:
Section
Qualifications of Petrographers and Use of Technicians 4
Purposes of Examination 5
Apparatus 6
Selection and Use of Apparatus 7
Samples 8
Examination of Samples 9
Specimen Preparation 10
Visual and Stereomicroscope Examination 11
Polarizing Microscope Examination 12
Paste Features 13
Report 14
1.4 The values stated in inch-pound units are to be regarded as the standard. The SI units in parentheses are provided for
information purposes only.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use. A specific hazard statement is given in 6.2.10.1.
2. Referenced Documents
2
2.1 ASTM Standards:
C125 Terminology Relating to Concrete and Concrete Aggregates
C215 Test Method for Fundamental Transverse, Longitudinal, and Torsional Resonant Frequencies of Concrete Specimens
C227 Test Method for Potential Alkali Reactivity of Cement-Aggregate Combinations (Mortar-Bar Method)
1
This practice is under the jurisdiction of ASTM Committee C09 on Concrete and Concrete Aggregates and is the direct responsibility of Subcommittee C09.65 on
Petrography.
Current edition approved June 1, 2014Jan. 1, 2017. Published June 2014March 2017. Originally approved in 1977. Last previous edition approved in 20132014 as C856
– 13.14. DOI: 10.1520/C0856-14.10.1520/C0856-17.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
C856 − 17
5
TABLE 1 Visual Examination of Concrete (1)
Coarse Aggregate + Fine Aggregate + Matrix + Air + Embedded Items
Composition:
A
Maximum dimension, in. or
mm, in the range> d>
Type: Type: color, by comparison with more than 3 % of total, Type, size, location;
National Research kinds of metal; other
Council Rock Color items
Chart (1963)
1 Gravel 1 Natural sand predominantly in spherical
2 Crushed stone 2 Manufactured sand color distribution: voids?
3 Mixed 1 and 2 3 Mixed 1 mottled less than 3 % of total,
4 Other (name) 4 Other (name) 2 even abundant nonspherical
5 Mixe
...
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